Chapter 7 glossary

Question 1

amino acids

Answer 1

building blocks of protein; link together end to end by peptide bonds to form the polypeptide chains that compromise proteins

Question 2

anagen phase

Answer 2

aka growth phase; hair phase during which new hair is produced

Question 3

catagen phase

Answer 3

brief transition period between the growth and resting phases of a hair follicle; signals the end of the growth phase

Question 4

COHNS elements

Answer 4

5 elements; carbon, oxygen, hydrogen, nitrogen, and sulfur that makeup human hair, skin, tissue, and nails

Question 5

cortex

Answer 5

fibrous protein layer of the hair; responsible for the strength, elasticity, and color of hair

Question 6

cowlick

Answer 6

hair that grows straight up or at a different angle than the other hair; usually more noticeable at the crown

Question 7

cysteine

Answer 7

amino acid with a sulfur atom that joins together two peptide strands

Question 8

dermal papilla

Answer 8

cone-shaped elevation found at the base of the hair bulb

Question 9

disulfide bond

Answer 9

strong chemical side bond that joins the sulfur atoms of two neighboring cysteine amino acids to create one cysteine, which joins together two polypeptide strands like rungs on a ladder

Question 10

eumelanin

Answer 10

consists of brown and black pigment and is the predominant pigment in black and brunette hair

Question 11

hair bulb

Answer 11

found at the base of the follicle; has a bulb shape and contains living cells that will form the hair strand

Question 12

hair cuticle

Answer 12

outermost layer of hair; formed from cells that resemble form singles on a roof; protects the cortex

Question 13

hair density

Answer 13

measures the number of individual hair strands on 1 square in. of scalp

Question 14

hair elasticity

Answer 14

ability of the hair to stretch and return to its original length without breaking

Question 15

hair follicle

Answer 15

tube like structure in the skin or scalp that surrounds the hair root and anchors the hair in the skin

Question 16

hair porosity

Answer 16

refers to ability of the hair to absorb moisture

Question 17

hair root

Answer 17

part of the hair located below the surface of the epidermis

Question 18

hair shaft

Answer 18

part of the hair that projects above the epidermis

Question 19

hair stream

Answer 19

hair flowing in same direction;; from follicles sloping in the same direction

Question 20

hair texture

Answer 20

thickness/diameter of an individual hair strand

Question 21

hydrogen bond

Answer 21

weak physical cross-link side bond that is easily broken by water or heat

Question 22

keratinization

Answer 22

process by which newly formed cells in hair bulbs mature, fill with keratin, move upward, lose their nucleus and die

Question 23

lanthionine bond

Answer 23

created when disulfide bonds are broken by hydroxide chemical hair relaxers and lose a sulfur molecule

Question 24

lanugo hair

Answer 24

short, fine hair that covers a fetus and sheds within a few weeks of birth

Question 25

medulla

Answer 25

innermost layer found in coarse hair; aka pith or core; absent in fine hair

Question 26

melanin

Answer 26

tiny grains of pigment in the cortex that give natural color to the hair

Question 27

peptide bonds

Answer 27

aka end bond; chemical bond that joins amino acids to each other, end to end to form a polypeptide chain

Question 28

pheomelanin

Answer 28

yellow to red pigment found in natural blonde to red shades of hair

Question 29

polypeptide chain

Answer 29

long chain of amino acids linked by peptide bonds

Question 30

salt bonds

Answer 30

weak physical cross-link side bond between adjacent polypeptide chains that is broken by changes in pH

Question 31

side bonds

Answer 31

bonds that cross link polypeptide chains and are responsible for the extreme strength and elasticity of human hair; account for one third of hair’s overall strength

Question 32

telogen phase

Answer 32

aka resting phase in the hair cycle that lasts until the fully grown hair is shed

Question 33

terminal hair

Answer 33

long, coarse, pigmented hair found on scalp, legs, arms, and body

Question 34

trichology

Answer 34

scientific study of hair and its diseases and care

Question 35

vellus hair

Answer 35

short, fine, unpigmented hair on the body; aka peach fuzz; less than one third inches long and can appear anywhere on skin except palms, soles of feet, and lips

Question 36

wave pattern

Answer 36

amount of movement or shape of the hair strand; described as straight wavy, curly, or coily

Question 37

whorl

Answer 37

occurs when hair leaves the follicles at an angle; air grows in a circular pattern on the crown of the head